"We established it after I had a conversation with a young mum who wanted to take her children to the cemetery to visit their dad and the children just couldn't go – it was just too distressing for them," Ms McKenzie-Ferguson told 891 ABC Adelaide's drive host Michael Smyth.

"He died as the result of a fork lift accident and the children were six and eight at the time.

"They couldn't understand why their daddy wasn't coming home anymore and cemeteries were big and scary."

She approached the Adelaide City Council with the concept of a memorial forest and the idea was supported by the council with tree plantings being held each year since.

Cricketer Phillip Hughes among those honoured

To mark International Day of Mourning, the organisation hosted a tree planting ceremony and planted 18 trees in the garden, one for each person killed in a workplace accident in South Australia in 2014, including South Australian cricketer Phillip Hughes.

"Even though he is not recognised under the legislation, he was actually an employee of SACA [South Australian Cricket Association]," Ms McKenzie-Ferguson said.

"Professional sports people aren't covered by the legislation ... but we recognise him as a worker and will be planting a tree for Philip."

A single tree was also planted in honour of all those who died as a result of industrial illness or disease, including asbestosis, mesothelioma and silicosis in the past year.

"If we planted one [tree] for every one of those victims then there would be no room left in Bonython Park," she said.

Ms McKenzie-Ferguson said work-related suicide was also a growing problem.

"It's a problem that we need to bring out in the open, because if we were talking about it a lot more then people would know that they are not alone and there are a lot of places that they can go for help, and we could prevent a lot more," she said.

Although occupational health and safety legislation had tightened over the years, Ms McKenzie-Ferguson said they had still planted between 15 and 22 trees each year for the past eight years.

Remembering those lost through workplace accidents

Ms McKenzie-Ferguson said the forest did not have plaques accompanying each planted tree, but the organisation was working on a special way to list those honoured.

"We have started work towards getting a memorial wall built and hope that we will have that in place by this time next year," she said.

"People can put the names of the loved ones on that wall ... and pay their respects there."

Although the planting of the trees began in 2003, Ms McKenzie-Ferguson said the organisation was happy to add trees each year for those killed at work prior to the commencement date.

"One of the trees we planted this year is for a gentleman who died in 1947."

Volunteers and Botanic Garden staff from the Adelaide City Council maintain the forest and surrounding grounds during the year.